A direct copper-catalyzed C−H bond oxidative sulfonylation of β-alkyl cyanoalkenes with sodium sulfinates was reported. The proposed mechanism suggests the existence of potential equilibrium between cyanoalkenes and allylic cyanoalkyl compounds, and the isomeric allylic cyanoalkyl compounds, due to their higher electron density, readily undergo addition reactions with sulfonyl radicals to selective afford cyanoallylic sulfones.

A systematic study of phosphine ligands, solvents, o-bromo-cinnamate esters was carried out for the [3+2] cyclization with benzo-fused 7-oxa-norbornadiene (Bz-OND). The best scenario involved the use of Pd(OAc)2 and dppf or DM-BINAP ligand, leading to highly Z-selective synthesis of indane-fused Bz-OND with (RO2C)methylidene units. The target products were furnished with ee of up to 43 %.

This study presents an efficient method for the palladium-catalyzed oxidative arylation of substituted 1H-indazole with various arenes and heteroarenes as coupling partners. Using an EWG at the C4 position of the 1H-indazole, a site-selective C7 oxidative arylation was successfully achieved. The catalytic system comprised Pd(OAc)2 as the catalyst, phenanthroline as the ligand, Ag2CO3 as the oxidant, and NaOH as the base.

A facile and efficient synthesis of polysubstituted imidazolidin-2-ones has been developed via an oxidative cyclization of activated acetyl amides and cyclic amidines mediated by iodosobenzene (PhIO). A mechanism was proposed for this transformation, which involves sequential intermolecular addition, Hofmann-type rearrangement and intramolecular cyclization reactions. The novel protocol features readily available starting materials, mild reaction conditions, simple execution, metal-free oxidative cyclization, and one-pot procedure.

The cobalt-catalyzed reaction between 1,3-dithiolanes and Grignard reagents, for the efficient synthesis of multi-substituted alkene products, is described. The method was applicable to a variety of benzylic dithiolane substrates, affording di-, tri-, and tetra-substituted 1,1-diaryl alkene products in good to excellent yields. The use of benzylic Grignard reagents with aryl aldehyde-derived 1,3-dithiolanes enabled access to natural product-derived stilbene architectures with exquisite E selectivity. The operational simplicity, low catalyst loadings, and scalability demonstrate the general utility of the method.

An efficient approach towards the synthesis of substituted spirochromans and dihydrocoumarins from a three-component reaction involving aromatic aldehydes, phenols and phenylene dithiolanes is described. This FeCl3 catalyzed reaction utilizes either aromatic aldehydes or their acetals for condensation with phenols to generate o-quinone methides in situ which further undergo a formal [4+2] cyclization with phenylene dithiolanes. Careful control of temperature allows direct access to dihydrocoumarins by the removal of the thioacetal moiety.

A visible-light-promoted O−H functionalization of 4-hydroxycoumarins with α-diazo esters was developed for the synthesis of 4-hydroxycoumarin ethers under photocatalyst-free conditions. Moreover, the three-component reaction of 4-hydroxycoumarins, α-diazo esters and THF generated a series of 4-hydroxycoumarin ether derivatives with alkoxyl spacers.

This manuscript describes the use of photoenzymatic catalysis to prepare lactams bearing quaternary stereocenters. This type of motif can be challenge to prepare stereoselectively, highlighting the opportunity for an enzyme to solve difficult challenges in chemical synthesis.

Here we report several useful synthetic strategies to azepino hi-indoles, that are structural units in natural products by using commercially available indole derivatives such as 7-bromo indole and 7-formylindole via palladium catalyzed cross-coupling reaction, ring closing olefin metathesis (RCM) as key steps. Later, we extended this strategy to seven-membered fused indoles containing dioxano and dioxocano derivatives via allylation, double bond isomerization and RCM sequence. Additionally, azepino indole having diene moiety was obtained by enyne metathesis and shown to be useful for Diels-Alder strategy. Along similar lines, we also report eight-membered fused azocino indole using Grignard reaction and RCM as key steps and we demonstrated that the product obtained is useful for Fischer indolization to obtain bis-indole derivative. Here several synthetically useful transformations were performed to generate diversity in the fused indole derivatives. All the compounds synthesized here are well characterized by NMR and HRMS data.

A novel and unique activation method for esters possessing a non-activated cyclopropyl moiety as a potential activating group is developed for acyl fluoride generation using a hypervalent iodine(III) reagent and Selectfluor. The resulting acyl fluoride, which is a versatile synthetic intermediate, was smoothly transformed into the various carbonyl compounds, in particular, amides. This protocol can be applied to the chemoselective activation of diester compounds.

In a recent paper in Chemistry – A European Journal, Nielsen and coworkers reported a deep study on the mechanism of the [2+2] cycloaddition-retroelectrocyclization (CA-RE) inducing the formation of 1,1,4,4-tetracyanobutadienes (TCBD), which is now suggested to be autocatalytic.

A Lewis base catalyzed C-S bond formation through thiocyanation of methyl C(sp3)-H bond is reported. The reaction works with diverse array of indoles to furnish thiocyanated products in good yield. The developed method is also applied for the synthesis of phercaptoline (hypotensive agent) and umifenovir (antiviral drug).

We disclose a strategy for union of N-allylamines and mono-carbonyl compounds which can be performed under redox-neutral and waste-free conditions, and promoted through concerted action of B(C6F5)3 and a N-based Brønsted base. A wide variety of α-alkylated carbonyl compounds may be synthesized, through the reaction of an in situ generated iminium intermediate and boron-enolate. Furthermore, we demonstrate that cooperative functions of B(C6F5)3, a chiral Zn-based complex and an amine can be exploited for stereoselective α-alkylation of glycinate Schiff bases.

The reactivity of N-Heterocyclic carbene (NHC)-bound alkynyl acyl azoliums was under explored in chemistry. We herein reported an NHC-catalyzed [3+3] annulation of alkynyl acyl azoliums with β-keto esters. The strategy features mild reaction conditions and exhibits broad substrates scope, delivering a wide range of tri-substituted α-pyrones in moderate to excellent yields (up to 95%). This approach extends the reactivity of alkynyl acyl azoliums to β-keto esters binucleophiles.

Biodegradable plastics synthesized from chiral organic acids have the potential to replace petroleum-based plastics. Poly[(R)-3-hydroxybutyric acid] is highly biodegradable, but have poor thermal properties. Copolymerization of (R)-3-hydroxybutyric acid with l-lactic acid as monomers improved the thermal properties while maintaining its excellent biodegradability. Copolymers with a high (R)-3-hydroxybutyric acid unit ratio degraded well in activated sludge.

The asymmetric aza-Friedel-Crafts-type reactions of indol-3-ones with 1- and 2-naphthols are developed to access structurally distinct chiral 2-(hydroxynaphthyl)-indolin-3-ones and tetrahydrofuroindoles, respectively.

A mild and sustainable transition metal, base and external oxidant-free electro-oxidative method has been devised for regioselective trifluoromethylation of imidazo[1,2-a]pyridines employing cost-effective and shelf-stable Langlois′ reagent. The universality of this economically viable lucrative protocol delivers a wide range of substrates with various functionalities, gram-scale electrosynthesis, and synthetic derivatization. Cyclic voltammetry and various control experiments confirm the radical mechanism of the reaction.

Herein, we report the synthesis of cyclic ketone-fused pyrazoles via [3 + 2] annulation reaction between hydrazones and cyclic enones (five-, six- and seven-membered) catalyzed by Cu(II) under aerobic conditions. These compounds were further functionalized by reactions such as Suzuki–Miyaura cross-coupling, Heck coupling, and Aldol reaction to afford diverse molecular scaffolds in good yield, selectivity and functional group tolerance.

In this work, we report the regiospecific and stereoselective synthesis of novel pyrrolo thioxoimidazolidinones with promising biological activities due to the inherent pharmaceutical properties of thioxoimidazolidinone core. The reaction of different thioxoimidazolidinones with trans-4-ethoxy-1,1,1-trifluorobut-3-en-2-one (ETFBO) yields bicyclic 1,3-diaza heterocycles bearing the trifluoromethyl (CF3) moiety. Our investigation involved both depth experimental analysis and theoretical calculations to fathom out the mode of reaction of this building block and elucidate the underlying mechanism operating for the observed reactions. Remarkably, this unusual mechanism retained the ethanol moiety from the building block in the final products, deviating from conventional nucleophilic reactions reported in the literature.

The alkylation of a nitride ligand of a post-modified Mo(V) complex was achieved with MeOTf (1a) and EtOTf (2a), respectively. However, different from the known Mo(VI) nitride complexes where the alkyl group can be deprotonated by strong bases to form a ketimide for the next progressive reactions leading to nitrile, 1a and 2a can only be reduced to highly stable Mo(IV) imido complexes by NaH. Upon treatment with fresh PhCH2OTf, a new dinuclear Mo complex was isolated with N2 release, instead of benzylation of the nitride ligand.